Many patents have been issued pertaining to the manufacture of magnetic media such as audio tape, video tape, floppy discs and hard discs for computers and the like. Such giants of industry around the world as Three M Company and Ampex in the U.S.A., B.A.S.F. in Germany and Sony, JVC and Fuji in Japan are among the many companies producing such products.
In all the products being currently produced organic solvent systems are employed. Today's health and safety requirements greatly add to the cost of these magnetic media due to the implementation of solvent recovery systems. Also the loss of solvent due to volatilization, if there is no recovery system, is not only a health hazard to workers, but is of great expense to the manufacturer; and the fire and explosion hazard which effects insurance costs. Air pollution prevention means, such as scrubbers for removal of organic vapors are high in cost.
There is a need, therefore, for a mechanism to reduce such added manufacturing costs. Such a procedure is found in the instant invention which eliminates the use of organic solvents.
It is an object of this invention to provide a binder system for magnetic particles that is free from organic solvent.
It is another object to provide a binder system for magnetic particles comprising an aqueous dispersion.
Yet another object is to provide a water based binder for magnetic particles that gives rise to excellent adhesion between said particles and the coating substrate (base).
It is a yet further object to prepare a water based dispersion magnetic media that is suitable for full range recording and reproduction.
A still further object is to provide lower cost, high quality magnetic tapes for audio and video and computer useage as well as floppy and rigid metallic discs.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others and the products possessing the features, properties and relation of elements which are exemplified in the following detailed description and the scope of the application of which will be indicated in the appended claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.